Autism is not a disease, but a developmental disorder of brain function. People with classical autism show
three types of symptoms: impaired social interaction, problems with verbal and nonverbal communication
and imagination, and unusual or severely limited activities and interests. Symptoms of autism usually appear
during the first three years of childhood and continue throughout life. Although there is no cure, appropriate
management may foster relatively normal development and reduce undesirable behaviors. People with
autism have a normal life expectancy.

Autism affects an estimated two to 10 of every 10,000 people, depending on the diagnostic criteria used.
Most estimates that include people with similar disorders are two to three times greater. Autism strikes
males about four times as often as females, and has been found throughout the world in people of all racial
and social backgrounds.

Autism varies a great deal in severity. The most severe cases are marked by extremely repetitive, unusual,
self-injurious, and aggressive behavior. This behavior may persist over time and prove very difficult to
change, posing a tremendous challenge to those who must live with, treat, and teach these individuals. The
mildest forms of autism resemble a personality disorder associated with a perceived learning disability.

What are some common signs of autism?

The hallmark feature of autism is impaired social interaction. Children with autism may fail to respond to
their names and often avoid looking at other people. Such children often have difficulty interpreting tone of
voice or facial expressions and do not respond to others' emotions or watch other people's faces for cues
about appropriate behavior. They appear unaware of others' feelings toward them and of the negative
impact of their behavior on other people.

Many children with autism engage in repetitive movements such as rocking and hair twirling, or in
self-injurious behavior such as biting or head-banging. They also tend to start speaking later than other
children and may refer to themselves by name instead of "I" or "me." Some speak in a sing-song voice
about a narrow range of favorite topics, with little regard for the interests of the person to whom they are
speaking.

People with autism often have abnormal responses to sounds, touch, or other sensory stimulation. Many
show reduced sensitivity to pain. They also may be extraordinarily sensitive to other sensations. These
unusual sensitivities may contribute to behavioral symptoms such as resistance to being cuddled.

How is autism diagnosed?

Autism is classified as one of the pervasive developmental disorders. Some doctors also use terms such
as "emotionally disturbed" to describe people with autism. Because it varies widely in its severity and
symptoms, autism may go unrecognized, especially in mildly affected individuals or in those with multiple
handicaps. Researchers and therapists have developed several sets of diagnostic criteria for autism. Some
frequently used criteria include:1

Absence or impairment of imaginative and social play

Impaired ability to make friends with peers

Impaired ability to initiate or sustain a conversation with others

Stereotyped, repetitive, or unusual use of language

Restricted patterns of interests that are abnormal in intensity or focus

Apparently inflexible adherence to specific routines or rituals

Preoccupation with parts of objects

Children with some symptoms of autism, but not enough to be diagnosed with the classical form of the
disorder, are often diagnosed with pervasive developmental disorder - not otherwise specified (PDD -
NOS). The term Asperger syndrome is sometimes used to describe people with autistic behavior but
well-developed language skills. Children who appear normal in their first several years, then lose skills and
begin showing autistic behavior, may be diagnosed with childhood disintegrative disorder (CDD). Girls
with Rett's syndrome, a sex-linked genetic disorder characterized by inadequate brain growth, seizures,
and other neurological problems, also may show autistic behavior. PDD - NOS, Asperger syndrome,
CDD, and Rett's syndrome are sometimes referred to as autism spectrum disorders.

Since hearing problems can be confused with autism, children with delayed speech development should
always have their hearing checked. Children sometimes have impaired hearing in addition to autism. About
half of people with autism score below 50 on IQ tests, 20 percent score between 50 and 70, and 30
percent score higher than 70. However, estimating IQ in young children with autism is often difficult
because problems with language and behavior can interfere with testing. A small percentage of people with
autism are savants. These people have limited but extraordinary skills in areas like music, mathematics,
drawing, or visualization.

What causes autism?

Autism has no single cause. Researchers believe several genes, as well as environmental factors such as
viruses or chemicals, contribute to the disorder. Studies of people with autism have found abnormalities in
several regions of the brain, including the cerebellum, amygdala, hippocampus, septum, and mamillary
bodies. Neurons in these regions appear smaller than normal and have stunted nerve fibers, which may
interfere with nerve signaling. These abnormalities suggest that autism results from disruption of normal
brain development early in fetal development. Other studies suggest that people with autism have
abnormalities of serotonin or other signaling molecules in the brain. While these findings are intriguing, they
are preliminary and require further study. The early belief that parental practices are responsible for autism
has now been disproved.

In a minority of cases, disorders such as fragile X syndrome, tuberous sclerosis, untreated phenylketonuria
(PKU), and congenital rubella cause autistic behavior. Other disorders, including Tourette syndrome,
learning disabilities, and attention deficit disorder, often occur with autism but do not cause it. For reasons
that are still unclear, about 20 to 30 percent of people with autism also develop epilepsy by the time they
reach adulthood. While people with schizophrenia may show some autistic-like behavior, their symptoms
usually do not appear until the late teens or early adulthood. Most people with schizophrenia also have
hallucinations and delusions, which are not found in autism.

What role does genetics play?

Recent studies strongly suggest that some people have a genetic predisposition to autism. Scientists
estimate that, in families with one autistic child, the risk of having a second child with the disorder is
approximately five percent, or one in 20, which is greater than the risk for the general population (see
"What is autism?"). Researchers are looking for clues about which genes contribute to this increased
susceptibility. In some cases, parents and other relatives of an autistic person show mild social,
communicative, or repetitive behaviors that allow them to function normally but appear linked to autism.
Evidence also suggests that some affective, or emotional, disorders, such as manic depression, occur more
frequently than average in families of people with autism.

Do symptoms of autism change over time?

Symptoms in many children with autism improve with intervention or as the children mature. Some people
with autism eventually lead normal or near-normal lives. However, reports from parents of children with
autism indicate that some children's language skills regress early in life, usually before age three. This
regression often seems linked to epilepsy or seizure-like brain activity. Adolescence also worsens behavior
problems in some children with autism, who may become depressed or increasingly unmanageable.
Parents should be ready to adjust treatment for their child's changing needs.

How can autism be treated?

There is no cure for autism at present. Therapies, or interventions, are designed to remedy specific
symptoms in each individual. The best-studied therapies include educational/behavioral and medical
interventions. Although these interventions do not cure autism, they often bring about substantial
improvement.

Educational/behavioral interventions: These strategies emphasize highly structured and often
intensive skill-oriented training that is tailored to the individual child. Therapists work with children to
help them develop social and language skills. Because children learn most effectively and rapidly
when very young, this type of therapy should begin as early as possible. Recent evidence suggests
that early intervention has a good chance of favorably influencing brain development.
Medication: Doctors may prescribe a variety of drugs to reduce self-injurious behavior or other
troublesome symptoms of autism, as well as associated conditions such as epilepsy and attention
disorders. Most of these drugs affect levels of serotonin or other signaling chemicals in the brain.

Many other interventions are available, but few, if any, scientific studies support their use. These therapies
remain controversial and may or may not reduce a specific person's symptoms. Parents should use caution
before subscribing to any particular treatment. Counseling for the families of people with autism also may
assist them in coping with the disorder.

What aspects of autism are being studied?

The NINDS is the Federal Government's leading supporter of biomedical research on brain and nervous
system disorders, including autism. The NINDS conducts research in its laboratories at the National
Institutes of Health, in Bethesda, Maryland, and supports research at other institutions through grants.

NINDS-supported research includes studies aimed at identifying the underlying brain abnormalities of
autism through new methods of brain imaging and other innovative techniques. Some scientists hope to
identify genes that increase the risk of autism. Others are studying specific aspects of behavior, information
processing, and other characteristics to learn precisely how children with autism differ from other people
and how these characteristics change over time. The findings may lead to improved strategies for early
diagnosis and intervention. Related studies are examining how the cerebellum develops and processes
information, how different brain regions function in relation to each other, and how alterations in this
relationship during development may result in the signs and symptoms of autism. Researchers hope this
research will provide new clues about how autism develops and how brain abnormalities affect behavior.

Where can I get more information?

For more information on autism, you may wish to contact:
National Institute of Mental Health
5600 Fishers Lane, Room 7C-02
Rockville, Maryland 20857
(301) 443-4513